Implantable medical devices for treating irregular contractions of the heart with electrical stimuli are well known in the art. Some of the most common forms of such implantable devices are defibrillators and pacemakers. Various types of electrical leads for defibrillators and pacemakers have been suggested in the prior art.
A broad group of those cardiac leads may be characterized by the fact that they are placed transvenously. These leads are introduced into the patient's vasculature at a venous access site and travel through veins to the locations where the leads' electrodes will implant in or otherwise contact coronary tissue. One large subfamily of the group of transvenously-placed leads are those that are implanted in the endocardium (the tissue lining the inside of the heart) of the right atrium or ventricle. Another subfamily of the group of transvenously-placed leads are those that are placed in the branch vessels of the coronary venous system to stimulate the left ventricle.
In general, directing a lead through a patient's vasculature can be a challenging proposition for a cardiac physician. For example, those leads that are placed in a branch vessel of the coronary venous system must be navigated to the right atrium of the heart, through the coronary sinus ostium, through the coronary sinus, and then into a desired branch vessel. To assist in such lead placements, a physician will typically use a device such as a guide wire or catheter with a pre-formed bend at its distal end. By rotationally manipulating the proximal end of the device, the distal end of the device can be pointed in a preferred direction, for example, toward a branch entrance. After the device has been placed, a lead will then follow either over the guide wire or within the catheter to the electrode placement site.
On occasion, a physician might wish to deploy a lead without first navigating another device in advance to the electrode placement site. The flexible nature of leads, though, is such that they exhibit very little inchessteerability inches or distal response to proximal manipulation. One response to this problem is to deploy a lead with a stylet or guide wire (hereafter simply referred to as a stylet) residing in the lead's central lumen to provide shape and steerability to the lead. The stylet would then be removed when lead placement was achieved.
Another response is to pre-form the distal end of the lead with a curvature adapted to facilitate access of particular anatomic features, for example, branch veins of the coronary sinus. It can be difficult to properly align the distal end of the lead to the branch veins so as to take advantage of the distal curvature of the lead. There is a need in the art for a device and method for aligning the distal end of an electrical lead with desired anatomical features.